JV Puleo

My 1910 Mitchell "parts car" project

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Got to tell you joe, there are times I just like stopping everything I’m doing, sit down in my easy chair, and look at something that just amazes me as I really enjoy learning something new.  Sometimes it can be about our planet and it’s beautiful nature or sometimes it can be something hard and man made like aircraft for example . I can tell you your posts hit that “fix” every time. I just enjoy looking at everything, from the equipment, to the different metals, your work, and what you do with all of it. I really don’t know of a better thread than yours. It’s pretty damn incredible. Of course I’m not knocking any of the other posters and their work but because they all know the kind of work involved, I’m willing to bet most if not all agree with me.

 

I do have one complaint though. There’s so much info and great pictures to look at that it takes me forever to get done looking at it all! Last night I fell asleep with my damn iPad on my lap and when I woke up, it was still on your thread! 😂 

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Posted (edited)

Stop it! You're embarrassing me.

Your thread and Mike's are every bit as interesting... I'm especially jealous of your spring making. That is something I've yet to learn.

I actually finished the pump this morning - it's nice to really finish something even though I'm years for finishing the car. I started by making 3 brass supports for the pump leathers. These are just washers but I wanted them to a specific size. For this I made this little "wahser maker". It is just a piece of 3/4 stock with a 5/1/6 hole reamed through it and a 5/16 cap screw.

 

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The brass plates are the same material I used for the tops of the lifter caps. To make washers, you can either turn a square piece round or cut off a round piece but in the latter case, it is tough to get them thin enough unless you grind them. I had intended to do that, but this idea came to me and I had the brass stock already cut for something else I'd changed my mind about.

 

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It takes time to turn it down because you don't want to take a deep cut when the corners are hitting the tool... you are relying entirely on the friction between the pieces to keep it from spinning so you can't exceed its value. I turned all three pieces down to 1.1", then took one off and turned the other two down ti .875

 

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I had to punch bigger holes in the leathers as well and that proved much easier than I'd expected. Then all the peices were assembled on the pump shaft.

 

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And I assembled it.

 

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I tried it in my pan of oil and it worked perfectly. The stroke is about 4-1/2" so it pumps about 4" cubic inches of oil per stroke. I don't know how that relates to the rest of the system but probably 4 or 5 strokes and it should be full.

Now I'm at loose ends and have to decide what to do next.

Edited by JV Puleo (see edit history)
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Now I have to think about the next round of tests. I need to simulate the main bearings... so I polished this piece of 2" tubing (the mains are a nominal 2" in diameter).

 

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This is the fixture I used to make the intake manifold. The hole in it is 2" so I am going to drill and tap it for the three flare fittings that will connect to the mains.

 

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This is not a very scientific job... the clearance will probably be about .002 but the tube really isn't round like a crankshaft. The polishing did remove some surface so I clamped it up and measured it with plastigage.

 

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This is about .004 clearance - not perfect but certainly good enough for this test. There are five connections, three to the mains and two smaller ones to the pistons. I'm going to leave the piston connections open because I don't know if the piston skirts cover them 100% of the time. The main bearing oil lines are 1/4" and the piston lines 3/16 so at worst I'll get a little less oil pressure than I will when it is installed on the car.

 

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I'm not sure what the weekend holds - if it rains I'll be in here both days. If it doesn't, I'll have to take a day off to mow the grass.

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16 hours ago, JV Puleo said:

Now I'm at loose ends and have to decide what to do next.

 

Well Joe, you can always come and help me!

 

11 hours ago, JV Puleo said:

I'm not sure what the weekend holds - if it rains I'll be in here both days. If it doesn't, I'll have to take a day off to mow the grass.

 

That's the reason I didn't seem to get much done this week! It's very annoying that it grows so fast in the good weather.

 

I am interested to know how your hand pump system will work. I am sure it will become clear in later posts. The pump sucks up the oil from the sump via a one way valve? Then the pump, on the down stroke, pumps it to the engine bearings? Does this side also have a one way valve? Or am I missing a point? The pump looks great and I like the idea of the making a test rig of the main bearings.

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Posted (edited)

In theory (meaning I still don't know if it will work) the hand pump sucks oil up from the sump and pumps it into the oiling system - the pump, oil filter, oil manifold and the lines going to the main bearings. It should also give me a way to check at what pressure the relief valve opens without running the pump. When there is pressure, the pump shaft is screwed into the top cap of the hand pump, effectively taking the hand pump out of the system. I think I can do this with only one "one-way" valve. I will be using a gate valve which reacts to a very low change in pressure and does not have a "ball in a cage" to get gummed up and stuck. But...it's all theory until it's tested and works!

 

There is no question that the vane pump develops suction but, unlike practically all other cars, the oil pump is considerably above the level of the sump so even with relatively good suction it still has to lift the oil before it can be distributed to the bearings. The car is also intended to be crank started so there is no "turning it over until the pressure comes up" unless you want to give yourself a heart attack. My guess is that, once warmed up, the hand pump will not be needed and it will only come into play when the car has been standing for a long time - like days or weeks.

 

Further on the Humber - lightening the reciprocating parts, especially the pistons by going to aluminum,  decreases stress on the mains and rods so a corresponding rise in compression makes no effective change. The problem is, I have no idea how to do the math to figure out what the "corresponding" value is...so I'd just guess.

Edited by JV Puleo (see edit history)
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Thanks Joe, I now understand. As to, "unless you want to give yourself a heart attack", been there, had one, don't really need another!

 

Humber - It will be interesting to see the difference in weight between the original pistons and the aluminium pistons, when I finally decide on the pistons to use.

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The original iron pistons in my Mitchell are astronomically heavy...the heaviest piston I've ever seen for a passenger car and, I think, heavier than the iron pistons that came out of a friends Wisconsin engine which are 3/4" larger in diameter. My aluminum pistons are half the weight and I haven't finished machining them. When done, I expect they will be close to 1/3 of the weight of the originals. The same can be said for the connecting rods. I once did calculations to see how much reciprocating weight I was removing and came up with a figure in excess of 20 lbs. That is taking a lot of stress off the bearings which I expect will allow for a slightly raised compression ratio and still leave the bearings less stressed but I do wish I had enough knowledge of advanced math (my weakest subject) to do fine calculations on this.

 

I've no idea what the high rpm of the Humber was but I strongly suspect that with careful balancing of the parts and dynamic balancing of the crank and flywheel (the machines for this weren't developed until the mid-1920s or early 30s) you can safely increase the rpms by 25%. When you do the new pistons, use hollow gudgeon pins...the wall thickness need not be any more than 3/16" if the diameter is up around 3/4". That will save weight without sacrificing strength. I'd also use circlips on the ends and let them float. At the time, they believed the pins had to be locked in place and I'll bet your pistons have little locks in the pin bosses to hold them rigid...probably one fell out which is why the bore is scored.

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I spent the entire day on the test stand...first deciding how to configure it. I have a good idea of how it will be set up on the engine - which is the important part but I hadn't anticipated how difficult it would be to find a way to get everything on the test rig. The first step was to turn two aluminum pins to hold the oil manifold. I was going to use two pieces of 3/4" pipe but couldn't think of a way to make them really secure.

 

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With that done, putting the rest together just took time since I had to try the parts and then disassemble it for the next step. I still have to plumb everything...which will probably take even longer.

 

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One of my friends just did a new kitchen. The varnished plywood are his old kitchen cabinets. Since the house was built around 1960, it is really good stuff...predating particle board and MDF.

 

 

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Even your test rig looks a work of art.

 

Yesterday, I somehow missed seeing your post regarding pistons. Thank you Joe for all the information. I have taken note and written it in my note book for future reference.

 

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Would the 'notch' in the side of the gudgeon pin hole be for a locking pin?

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Maybe, but it isn't a system I am familiar with. Usually something screws in from the bottom - inside the piston. If it was for a lock, and the lock is missing, it accounts for the scored bore. That was a fairly common problem because none of the locking systems were foolproof. It's a case where we actually have learned something in the last 80 years... floating pins work just as well and are easier to keep from rubbing the inside of the cylinder.

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I don't know about "work of art"... but it should be sturdy - which is important. I have to fiddle with the plumbing today. It's a holiday in the US - Memorial Day (which, incidentally, takes place more or less on the anniversary of the great review of the Union Army in Washington at the end of the Civil War. It took two days for the troops to pass the reviewing stand.)

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Well, it looks a lot more interesting than some of the modern art I've seen!

 

It's also a holiday today in the UK. It used to be called Whitsun and started  as the Monday after Pentecost. The Banking and Financial Dealings Act 1971, moved this bank holiday to the last Monday in May, following a trial period of this arrangement from 1965 to 1970.

 

I am glad that I didn't have to be on the reviewing stand for the two days it took the Union Army to pass the reviewing stand!

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The test stand is starting to look like a Rube Goldberg machine - our British friends would say Heath Robinson.

 

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Tomorrow morning I'll have to stop at the market and get a bigger baking pan. I also have a lot to learn about bending tubing without kinking it.

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Posted (edited)

Much to my relief, it works!

 

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Clearly, there are issues I have to address. The end caps for the oil filter housing are leaking badly so I'll take it apart and put O rings in there as gaskets. The real problem - and I don't think it is a serious one, is that it produces too much oil pressure.

 

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This is the actual gage that will go on the dashboard and I wanted it to run in the middle at 15 lbs. It's pegged over so I don't really know what the pressure is but I'll bring in my remote gage, left over from my days in the garage, to get a more accurate reading. I really wanted to know if the old gage worked but I don't want to damage it. I suspect a weaker spring in the relief valve will be the answer so I'll have to figure that one out as well but overall I'm pleased. When you make anything as complicated - and experimental as this some tweaking is inevitable.

 

I also ordered some Wood's Metal. I want the oil lines to be curved and spiraled in places rather than using the solder elbows and it is important to me that the curves be uniform and look "factory". After looking at all sorts of youtube ideas on how to bend tubing, I decided that maybe the best way would be to do what was done at the time. Oddly enough, when I found a supplier for the metal, the web site listed the uses of Wood's metal and one was "tube bending."

 

EDIT:  I should have said "professional". Nothing about this engine, except the castings, is going to look as if it came from the Mitchell-Lewis factory.

Edited by JV Puleo (see edit history)
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Posted (edited)

I couldn't leave it alone so I took the oil filter housing apart and put in the O rings. (I have a cigar box full of them, inherited from a now-deceased friend.) That solved the leak.

Then I took the spring out of the relief valve so it would run fully open.

You can see the oil returning to the "sump".

 

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With the spring out, the pressure went up to about 10 lbs, then fell back to 2 or 3 lbs and stayed there.

 

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So, I think a weaker spring is in order... figuring out exactly how weak will be a matter of trial and error but it looks as if this entire adventure has been successful.

Edited by JV Puleo (see edit history)
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Hello Joe, 

I have been away for a week taking care of family things and spending some quality time with my wife.  We are back now!  I am impressed with your engineering and also you test set-up.  When I did a similar oiling change on my Locomobile, we were confronted by needing to "dial in" the oil pump relief valve.  The original setting was putting to much back pressure on the drive for the oil pump and would most certainly cause premature wear and result in system failure.  We went from an out put pressure of near 50 PSI to a much calmer but way better setting of 20 PSI.  The back pressure on the drive was GREATLY reduced.  When I considered what the old original design was simply a "drip" my new system is very much a "time period" betterment!  Keep up the fine work you are doing to get your Mitchell running.

Al

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Posted (edited)

I had much the same thought although my biggest worry was that the pump would not produce sufficient volume. Boy was I wrong about that...it looks as if it might produce too much volume. I also re-did the math this afternoon, calculating the speed of the motor on the test stand and the reduction due to the sheaves. I did this before but I've lost the notes - and I think I did it wrong the first time because this time I came up with completely different figures. I think I calculated it with one motor and then used a different one – failing to notice that this one is a 725 RPM motor while the original was 1625. The result is that the pump on the test stand is only turning at 322 RPM - really a fast idle so, if anything, I have too much oil. But, I made the output tube the same size as the input so I don't think it can generate much pressure no matter how much oil is going through it. Getting a light enough spring, in the dimensions I need is the real problem. I have spent about three utterly pointless hours looking at spring catalogs and finally decided that I am not going to find what I'm looking for... so, I'm giving some thought to a spring winding jig. I think I can make a pretty good one and it's one of those skills I've put off but could really use.

 

EDIT: I don't think the original oiler was a drip system - although they were often called "drip oilers." The little separate pumps in an oiler box actually generated quite a lot of pressure. What they didn't generate was volume, both because they were tiny plunger pumps and because, at the time it wasn't understood that the volume of oil was important. They were following steam and stationary engine practice, both of which had much slower turning engines than an automobile, and usually had tiny oil lines running to the bearings. No matter how much pressure there was, there simply couldn't be much volume.

Edited by JV Puleo (see edit history)
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I'm really pleased for you that it all works OK, after all your hard work on this part of the project. I am very glad you shared it with us. I am still learning a lot from your posts, as I am sure are many others. Keep up the excellent work and posts

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Hello Joe,

Your approach would put you into the category of a Henry Ford or any of the other early guys interested and driven to design and build a better "thing".  I know the feeling of reward and satisfaction when something comes together and works.  We, in this hobby, all have our hot buttons that keep us going.  Our interests are basically similar and we are all working to save a piece of history for the future but how we get there is different for each of us.  I  share your mindset and approach.  You still have lots to do and many issues to resolve, don't loose your steam!

Al

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Posted (edited)

Of all the springs I’ve made out of round wire, I always start with piano wire so there’s no treating involved. I had a huge box full of all different gauges of wire from my RC airplane hobby that’s starting to dwindle down now that I’ve made a few. Joe, I believe they make compression springs using the lathe with a piece of round stock. Should be a walk in the park for you. Just watch the spring making episode of “how it’s made”! (I actually saw that episode and it was really interesting)

Edited by chistech (see edit history)
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As a good example of working when I'm tired...I spent hours looking for a spring and had the wrong dimensions. I'm going to go ahead and make some in any case. It's a skill I ought to have and I also suspect isn't difficult with the lathe to turn it. I have a coil of music wire I bought years ago to experiment with.

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Posted (edited)

This morning I brought in my remote oil pressure gage - a Snap-on tool I must have bought 35 years ago and haven't used since. I was a little surprised I found it so easily. I wanted to get the real pressure reading and the gage goes up to 100 lbs. I hooked it up, with the spring back in and it immediately shot up to 50 lbs. and the pressure dislodged the core plug on the back of the pump causing a rather dramatic leak.

 

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I can't say I was too surprised. It was weeping oil there even without pressure and I was going to do something about it in any case. I took the back off the pump - and here the dowel pins I'd put in worked perfectly, allowing me to take it off and replace it easily. I then got my camp stove out and soldered a new plug in place.

 

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It cleaned up really well - between the domed shape of the plug and the machined hole for it, I had no problem getting a good seal (or at least I hope so). If this had gone on the road it would be a real disaster. I can't do much more with the pump until I get or make a spring so I went back to the lifters. Until now I hadn't actually tested the hold-downs to make sure they all fit. Thankfully, they did.

 

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The hold-downs get little cross-shaped pieces on the bottom that engage notches in the rim of the lifter body and these are proving more difficult to make than I'd anticipated.

I cut 4 pieces of aluminum and milled one side to get it square.

 

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Then, measuring from the square end, drilled and reamed 1/2" holes in the center, 1" from the end.

 

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I put a piece of 1/2" ground stock through the holes so that all 4 pieces would be in equal alignment and milled the other end square. The holes aren't perfect - one is a little short of the center but I think I can take care of that later on.

 

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Then the edges had to be milled down so that the height was .783". Part of the difficulty with this comes from the fact that the hole in the center has to be perfectly aligned with the cross shape and all of the measurements are odd. I got that done, albeit .003 undersize and tomorrow I'll cut away the ends. This is more difficult to explain than it is to illustrate so I'm guessing you won't really know what I'm up to until I can show the finished product. I may not like the result but I bought enough material to do it again if I have to.

 

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Edited by JV Puleo (see edit history)
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Posted (edited)

 

 

I then milled notched in both ends...

 

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This is what I was aiming for but I was genuinely surprised when all four pieces fit. I was mentally prepared to do it over because this time I thought I'd designed something I couldn't make. These are locks that are intended to keep the lifters from turning but they have to be attached to the hold-downs, so they can be screwed down tight, in order to work.

 

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I also made a bushing for the center of the hold-down and ran out for a flat head cap screw to hold everything together. I've had enough trouble with Mitchell measurements that I want to do this one-at-a-time to make sure they work.  The two pieces were attached to each other on the car with everything lined up.

 

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This is what I ended up with.

 

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Then fixed it in a collet block and lined up so that the edge of the hold-down was parallel with the block.

 

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Then, one hole at a time, I drilled, countersunk and threaded them and then screwed in a 10-24 flat head cap screw.

 

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And here they are. To my relief, they all fit and I think they are interchangeable... but I'll save testing that for another day. There is still more to do here but I'm getting close to finishing this part of the job.

 

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Edited by JV Puleo (see edit history)
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